Speaking about returning to the role, Downey Jr said that he would "start another [Iron Man] tomorrow", but that is not a possibility due to the production timetable.

He said: "There are a lot of other considerations. But I also don't like the idea of leaving people hanging or leaving people in the lurch."

Downey Jr also said that his desire to tackle another character, in addition to future Sherlock Holmes films, could delay a return to his role as Stark.

He said: "My intent is to launch another franchise, independent of any that I can even imagine right now. My intent is to dominate the playing field for as long as I can, with my own challenges, with myself."

Ant-Man has been confirmed for Marvel Studios' third roster of films, with Doctor Strange and a Hulk reboot firm contenders for production.